This August 2012 image shows a record low sea ice level in the Arctic. The yellow line marks the previous low. The black line marks the median ice level in the last 20 years of the 20th century.

Washington — An annual assessment of climatic conditions in the Arctic shows record-breaking declines in summer sea ice, spring snow cover and the Greenland ice sheet.

The National Oceanic and Atmospheric Administration (NOAA) compiled the research, tapping the expertise of more than 140 contributors from 15 nations.

"The Arctic is changing in both predictable and unpredictable ways, so we must expect surprises,” said Jane Lubchenco, under secretary of commerce for oceans and atmosphere and the NOAA administrator.

She discussed the findings at a press briefing earlier this month. “The Arctic is an extremely sensitive part of the world and with the warming scientists have observed, we see the results with less snow and sea ice, greater ice sheet melt and changing vegetation.”

The Arctic Report Card has been annually reviewing conditions in the world’s northernmost region since 2006. The findings reveal 2012 to be a record-breaking year.

• Snow extent in the Northern Hemisphere hit a record low point in June.

• Arctic sea ice extent was the lowest in September since satellite observation began in 1979.

• Surface melting on the Greenland ice sheet covered about 97 percent of the surface in July.

• The length of the growing season has increased from 2003 to 2012.

“The record low spring snow extent and record low summer sea ice extent in 2012 exemplify a major source of the momentum for continuing change,” said Martin Jeffries, co-editor of the 2012 report and Arctic science adviser in the Office of Naval Research. “As the sea ice and snow cover retreat, we’re losing bright, highly reflective surfaces, and increasing the area of darker surfaces — both land and ocean — exposed to sunlight. This increases the capacity to store heat within the Arctic system, which enables more melting — a self-reinforcing cycle.”

That melting contributes to sea level rise, which is an ominous trend for low-lying island nations, coastal areas and the sizeable populations in those areas worldwide.

In an interview published in NOAA’s Climate Watch magazine as the 2012 report was released, Lubchenco said the Arctic may seem a remote and foreign place to people in lower latitudes, but the region influences environmental conditions worldwide.

“The changing interactions between the ocean and the atmosphere can affect weather patterns in the United States and in Europe,” Lubchenco said. “The biological changes in the Arctic also matter to people living outside the region. For example, changes in Arctic ecosystems can, in turn, affect migration patterns of birds that go from the Arctic to places at much lower latitudes.”

Despite the evidence of increased melting and diminished snow cover, the scientists did not find that Arctic air temperatures were notably higher in comparison to those of the past decade. But the other trends are adequate evidence of the rapidly changing Arctic.

Several industries are scoping out increased economic opportunities with the increased open water in the Arctic that’s resulted from warming. Shipping routes, previously iced in, may allow faster transit between the northern Pacific and northern Atlantic oceans. The same trend may drive the tourist industry to offer pleasure excursions through Arctic sea lanes.

Greater access by sea and moderation in the harsh environment may also provide more favorable conditions for resource extraction, such as oil drilling and mining.